The present disclosure relates to service assurance in cloud computing and, more specifically, to a system and method for license enforcement for data center monitoring applications.
Enterprise information technology (“IT”) management solutions which access internet protocol (“IP”) addressable infrastructure typically have licenses which restrict one or more of the number of managed items and the address range/list or name, in addition to one or more of node locking, time limits, and requirements for keys to unlock features.
When packets of data are transferred between devices in an IP network, a time to live (“TTL”) value is embedded in the TTL (i.e., IPv4) or Hop Limit (i.e., IPv6) field of the IP header of each packet of data. The TTL/Hop Limit field is an 8 bit binary counter value located in the IP header of all IPv4 and IPv6 packets respectively. The TTL value is initialized by the sender of the IP packet to a specific value between 1 and 255, and is reduced, according to IPv4 standards, by the amount of time it takes the device to process the IP Packet. In modern networks, this amount of time is almost always much less than 1 second. Thus, by convention for IPv4 and by standard for IPv6, such IP Layer 3 (“IP L3”) devices reduce the TTL field by 1 increment each time they process an IP packet. When the TTL counter field value has been reduced to zero, the IP packet with its data is discarded by the handling device (i.e., IP L3 router) and an ICMP message of “Time Exceeded” is sent to the sending device by the discarding device (i.e., the IP L3 router) informing it that the associated packet has been discarded. The TTL value is utilized in this manner to prevent data packets from circulating indefinitely in a network. Typical values that modern operating systems (e.g., Windows or Linux) use to initialize the TTL/Hop Limit field are in the range of 64 to 128. Thus, IP packets with an initial value of “64” can travel up to 64 IP L3 hops in a network before they are discarded (i.e., when the field reaches “0”).